by which files (hmm...why can't I unmount that file system over
there). Currently this is just the device and inode number of the
file backing the vnd, but hopefully consing up full pathnames can be
done at some point.
- guard against synchronous I/O completion
- avoid race conditions
- use bgetvp/brelvp to properly maintain the vnode holdcount
and clean/dirty buffer lists.
greater flexibility in its use. Additionally, add support for "geometry
emulation". This allows the "geometry" of the "disk" to be specified
at config time, providing near-perfect emulation of disklabel-less floppies,
CD-ROMs, etc., including non-512-byte sectors. If a geometry is not
specified at config time, a default based on 1M cylinders will be used.
